1. Field of the Invention
The present invention relates generally to medical devices, systems, and methods. More particularly, the present invention relates the closure and removal of a left atrial appendage or other tissue structure using a compliant compression body for isolating the structure near its base.
Atrial fibrillation is a relatively common condition characterized by a very rapid heart beat of the left and right atrium. While atrial fibrillation is not normally fatal itself, it has been associated with an increased risk of stroke. It is believed that the rapid heart beat causes blood to pool in the left atrial appendage which causes emboli that are released into the left atrium from where they can enter the cerebral vasculature, thus causing a stroke. In addition to stroke, the emboli can enter coronary circulation, potentially causing myocardial infarction, or can enter peripheral circulation, potentially causing peripheral vascular disease.
The risk of stroke in patients suffering from atrial fibrillation can be reduced in a variety of ways. For example, blood thinning drugs can be used to reduce the risk of clot formation. The use of blood thinners, however, is contraindicated in patients at risk of bleeding disorders.
More aggressive treatment protocols have been proposed which involve closing the left atrial appendage. Closure and excision may be performed in open surgical procedures, typically requiring the patient to be placed on by-pass and the chest to be opened through the sternum. Alternatively, thoracoscopic and other less invasive procedures have been proposed. U.S. Pat. No. 5,306,234 teaches the performance of beating heart procedures using otherwise conventional surgical techniques. The use of conventional techniques through small chest penetrations while the heart is beating can be difficult to perform. U.S. Pat. No. 5,865,791 describes an intravascular approach where tools are introduced through the vasculature and passed into the left atrium. The tools are used to ablate or fuse the left atrial appendage from the inside using energy, adhesives, or the like. The '791 patent also describes a thoracoscopic procedure where a tether is placed over the neck of the atrial appendage and tied off to achieve isolation. The '791 patent still further suggests other closure elements including sutures, staples, shape-memory wires, biocompatible adhesives, and the like. U.S. Pat. No. 6,488,689 describes a transpericardial procedure where the distal tip of the left atrial appendage is grasped and pulled backwardly through a capture loop which encircles the base of the left atrial appendage.
For these reasons, it would be desirable to provide improved apparatus, systems, and methods for less invasively closing the left atrial appendage and other body structures. Such apparatus, systems, and methods should be capable of being performed on beating hearts, should avoid the need to form a transeptal penetration to access the left atrium, and very importantly should result in tissue closure at the base of the left atrial appendage. In addition to the above, it would be still further desirable if the methods and protocols were relatively easy to perform and the closure element and other aspects of the device produce a secure closure. At least some of these objectives will be met by the inventions described herein below.
2. Description of the Background Art
Less invasive and other procedures for closing the left atrial appendage are described in U.S. Pat. Nos. 6,488,689; 5,865,791; and 5,306,234; and Published Application Nos. 2005/0154404 and 2004/0030335. Other tissue ligation tools and techniques are described in U.S. Pat. Nos. 6,790,172; 6,436,108; 6,051,003; 5,624,453; 5,507,797; and 4,257,419.